Comparision of Analgesic Efficacy of Plain Bupivacaine with Bupivacaine and Clonidine in Ultrasound Guided Transversus Abdominis Plane Block

This prospective randomized double blinded case control study was done at Government Rajaji Hospital, Madurai after obtaining Hospital Ethical Committee approval and informed consent from all the patients. 60 patients who underwent lower segment cesarean section under subarachnoid block were enrolled in this study. They were divided in to two groups of 30 each. Both groups received standard dose of 10mg 0.5% Bupivacaine in subarachnoid block. After the surgery when block level receded to T10 sensory level, ultrasound guided TAP block was performed bilaterally using posterior approach. The ultrasound was used to identify the correct position of needle and also the spread of local anaesthetic solution in the neurofascial plane between internal oblique and transversus abdominis muscle. Group BC received 20ml of 0.25% Bupivacaine with clonidine 0.5microgram/kg and Group B received 20ml of 0.25% Bupivacaine on either side. The hemodynamic parameters like pulse rate, blood pressure, respiratory rate, oxgen saturation and sedation score by means of Ramsay score was monitored after the performance of block. The analgesic efficacy was monitored by means of VAS score. The duration of analgesia was calculated from the time of performance of TAP block until the VAS score of 4 was obtained. The primary end point of study was when VAS score ≥4 was obtained. All data were analysed and the demographic profile, duration of surgery and hemodynamic parameters were comparable in both group without any significant difference. The average duration of analgesia was 516 minutes in bupivacaine and clonidine group compared to 277 minutes in plain bupivacaine group and this duration of analgesia was statistically significant in bupivacaine with clonidine group when compared to bupivacaine group. The sedation score of 3 was obtained in about 86.7% of the patients in bupivacaine and clonidine group compared to only 10% of patients in plain bupivacaine group. Thus the sedation score was significantly higher in bupivacaine with clonidine group but it was an arousable sleep. The incidence of complications like post operative nausea, vomiting hypotension and bradycardia was similar in both groups and it was not statistically significant. Thus the addition of clonidine to bupivacine extended the duration of analgesia without any significant side effects in ultrasound guided Transversus abdominis Plane Block. CONCLUSION: Ultrasound guided Transversus abdominis plane (TAP) block as a technique for providing postoperative analgesia is highly effective after caesarean sections. The addition of clonidine to bupivacaine in TAP block extended the duration of analgesia with minimal sedation when compared to plain bupivacaine without significant changes in hemodynamic parameters or complications. Ultrasound guided TAP block was easier to perform and provides reliable and effective analgesia